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ZF 4HP22 - temperature and cooling?

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Three key questions:

What's the operating temp range for the ZF 4 speed box?

Is the standard bogbrush cooler sufficient for a Defender in the desert?

Could I use a water temp sender to measure the fluid temp?

I'm taking my truck to Morocco in May - it's got a bogbrush cooler but I've no way of measuring the fluid temperature apart from a hand-held IR thermometer. Non-fault paranoia is setting in and with no adverse symptoms at all I'm now convinced it's going to melt or catch fire and kill me. Question is, chance it or "upgrade" it and risk a relatively untested bigger cooler?

If I did choose to "improve" it I've a 34(?) row cooler of unknown provenance, but I'd need to get pipes made up and mount it - hopefully in a way that won't crack the cooler by distortion or vibration, and which won't chafe the pipes anywhere which will leave me stranded. I'd put the water temp sender at one end of the new cooler; I'm aware that the fluid reverses direction but I'm thinking that any monitoring is better than none.

Basically, either way I expect to die alone in the desert. Which would you choose?

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Basically, either way I expect to die alone in the desert. Which would you choose?

:hysterical:

There's a temperature answer here.... may be worth considering: http://forums.bimmerforums.com/forum/showthread.php?964746-Operating-temp-range-of-E34-auto-trans-4HP22

The consensus of opinion on an auto is to keep the thing as cool as possible and it will extend it's life.

Having zero experience with the bog-brush cooler, I'd suggest installing a temp sensor here, and getting a feel for the reading. and also recording what the ambient temperature is at the readings you're getting.

You can then use a bit of crude math to calculate what you'll get in a hotter climate.

The formula is Q = m * cp * DT. As the m and cp can be presumed to be constant (for a rough calc)... DT is the Oil temp - Air Temp.... if we presume that the amount of heat generated and lost is the same..., then:

Oil temp Morocco = (Oil Temp peak (now) - Air Temp (now)) + Air Temp (peak) you expect in Morocco

It's crude math as there are a number of things that can affect the heat exchange, but add a margin on (10%) and you should not be too far out...

What I don't know is the maximum operating oil temp for the transmission

There is a manual here that seems to indicate there is a sensor on some of the transmissions (you may be able to use it).

http://www.jaguarclub.sk/service/powertrain%20-%20zf.pdf

There is a link / section on Ashcrofts website that discusses the FAQ's and temperature is mentioned, but the link in dead, here's the page, and here is a working link:

http://www.ashcroft-transmissions.co.uk/frequently-asked-questions/4hp22-faq-s.html

http://www.digi-panel.com/trannyoil.htm

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Dave - thanks, that link is great, I'll drop you an order for some temperature strips then add 30°C as a guesstimate for the Morocco temps as per Robert's suggestion.

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Discovery 300tdi autos have a temp switch in the pipe system , that tells you when its getting too hot . You can also use a full synthetic trans fluid (eg Redline) this will give you a bigger safety margin .

I have a 90 with the 300tdi auto fitted , and i used one of these as a cooler

http://www.ebay.co.uk/itm/Shogun-Pajero-Exceed-2-5TD-mk2-oil-cooler-engine-/310317646174?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item48405f815e

its about the same size trans cooler as fitted to utes and 4x4 when doing towing in Australia .

HTSH

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Why not fit a temp sender into the sump? That way you have a stable temp to work from. As said by others the bog brush isn't up to the job. Fit a mocal cooler. Make sure you use 1/2" dia hoses or you won't get the flow you require

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I think I can help here, Julie and I recently drove accross the Great Victorian Desert from South Australia (Coober Pedy) to Ilkurluka in Western Australia (1 November to 2 December 2013), average ambient temperatures were arround 45 degrees C.

My ZF4HP22 was a special built by Ashcrofts with uprated clutches and a ZF4HP24 oil pump. Even so at no time did the oil temperature light come on, our average speed was arround 25 KPH over the Anne Beadell that was corrugated enough to give you nose bleeds. even so the ATF became so hot you could not hold your hand on the oil lines - they were that hot !!! The standard oil cooler was/is fitted.

I'm in the process of replacing the ZF with a R380 not because of performance, -- the ZF was superb driving over 15 metre high sand dunes -- but because I got to thinking if it did give me any trouble I would simply be unable to fix it, whereas I can fix a mechanical box.

The only problem we has was when the corrugations and vibration caused one of the connections to the oil cooler to crack, dumping 50% of the ATF over the desert track. I "jerry" rigged a by-pass by cutting off the oil line unions and used a length of hose from my spares kit. For spare ATF to top up the gearbox I mixed up some diesel and engine oil - sufficient to get us the 130 kilometres to the only and next roadhouse at Ilkurluka where I drained it, dropped the sump, span the torque converter to remove all the hybrid home made ATF fluid, changed the ZF oil filter and refilled with fresh ATF - and 10K kilometres later it still works as good as new, but lesson learnt, ZF's are simply too complicated to fix easily so I'm changing to a manual with heavy duty clutch andf pressure plate etc.

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I think I can help here, Julie and I recently drove accross the Great Victorian Desert from South Australia (Coober Pedy) to Ilkurluka in Western Australia (1 November to 2 December 2013), average ambient temperatures were arround 45 degrees C.

My ZF4HP22 was a special built by Ashcrofts with uprated clutches and a ZF4HP24 oil pump. Even so at no time did the oil temperature light come on, our average speed was arround 25 KPH over the Anne Beadell that was corrugated enough to give you nose bleeds. even so the ATF became so hot you could not hold your hand on the oil lines - they were that hot !!! The standard oil cooler was/is fitted.

I'm in the process of replacing the ZF with a R380 not because of performance, -- the ZF was superb driving over 15 metre high sand dunes -- but because I got to thinking if it did give me any trouble I would simply be unable to fix it, whereas I can fix a mechanical box.

The only problem we has was when the corrugations and vibration caused one of the connections to the oil cooler to crack, dumping 50% of the ATF over the desert track. I "jerry" rigged a by-pass by cutting off the oil line unions and used a length of hose from my spares kit. For spare ATF to top up the gearbox I mixed up some diesel and engine oil - sufficient to get us the 130 kilometres to the only and next roadhouse at Ilkurluka where I drained it, dropped the sump, span the torque converter to remove all the hybrid home made ATF fluid, changed the ZF oil filter and refilled with fresh ATF - and 10K kilometres later it still works as good as new, but lesson learnt, ZF's are simply too complicated to fix easily so I'm changing to a manual with heavy duty clutch andf pressure plate etc.

Probably a good choice as they cost an absolute fortune to get fixed in australia FMHE

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A pal of mine has 300 auto disco and recently came back from Morocco

We drilled a hole in his sump and welded in a temp sender boss to monitor AT temp

I don't remember him mentioning a problem (engine coolant was the biggest climber I think) but he does have fill width allisport rad, inter cooler and AT oil cooler.

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How about a tapped and threaded banjo bolt? The one on the side of the transmission, that secures the oil cooler pipe, would seem a prime candidate.

Or.... P38 transmission oil coolers have a temp sensor on the side... kill two birds with one stone... a better cooler and a temp sensor for free. (V8's do, not sure on diesels?)

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Good shout on the cooler

Would not want to fit sensor to banjo, would restrict flow to almost zero

Sump plug is available on auto sump but positions the sensor very vulnerably.

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As I said, mine never came on and I think your worrying about nothing, but if you want to know at what temperature it brings the dash light on just test the temp sender in the fluid line by removing it and immersing it in oil on your hot plate at home with a temperature probe and see what temp it switches, simple as that. _ I'm assuming here that your LR has a temp sender in the oil supply to the oil cooler as does the Series 1 Disco, if your vehicle doesnt have one get a Disco oil line and sender and fit it.

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This is rather running away with itself. I took a wing off to fit the cooler I have in stock, then discovered that the stock item is a aircon condenser, and rather larger than I'd remembered. Am I being entirely ridiculous in considering piping it up as an oil cooler?

post-277-0-35292100-1390761577_thumb.jpg

It'll be rated for pressure well enough but the matrix might restrict the flow ... Though its sheer size would offset that. Can the box be overcooled?

Otherwise there's a P38 cooler on ebay which has a temperature switch. I don't currently have any monitoring beyond one of Dave Ashcroft's temperature strips as linked above, though I've not been for a run with it fitted yet.

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I really don't think an AC condensor is a good idea for oil cooling, it will be far too small bore, and bloody awkward to connect up AND pretty flimsy, they always get pierced by stones etc!

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I've just checked out a spare oil temperature sender off my Disco, - as stamped - it switches at 135 degrees C. As I said in my previous blurb I never had a problem with ATF oil over heating in 40 degree ambient air temperatures, I thnk you're worrying about nothing, the standard air cooled oil cooler should be fine..

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Boydie - you say your oil lines got too hot to touch on the Anne Beadell with the standard cooler - do you mean a radiator-style matrix cooler, or the bog brush one like in the foreground of my photo above?

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Mine is the bog standard Australian LR unit as fitted with the ZF auto box, and try holding a steel oil line at arround 135C :blush: !!!! from your blurb (no above photo was available) its the radiator style, the "bottle brush" unit was (I understand) the standard fitting for the V8 with a manual R380 gearbox and not fitted to the ZF auto's unless this was standard in cooler climates.

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Turbo, just a thought, does your car have air conditioning? I've reloacted my A/C condenser from in front of the radiator to under the roof rack to improve air flow through the radiator as well as the intercooler, it made a huge improvement.

Also form a small 2" wide 1/16" thick flat plate with a hexagonal cut-out for the cooling fan nut ( a lot of filling was involved here) with bolt holes to match the silicon drive, the end result is a fan that will constantly drive regardless of air temperature when the plate is fitted and bolted in place - with the advantage it's reasonably easilly removed for "normal" operation

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The V8 ZFs certainly got the bottle-brush type here (no cooler on UK R380s AFAIK), and that's what I'm using - though mine's a mongrel install anyway. It's worked fine so far, but I think I'll follow the advice and get a matrix-type cooler while it's apart. The aircon condenser I have is tempting but probably not really suitable, and might overcool it once I'm back in the UK anyway.

I don't have aircon on the truck, nor a roofrack as standard and I'm not wild about putting something up there where UK branches would tear it apart quite quickly.

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Interesting how my lt77 3.5 has a bogbrush box cooler but no engine oil cooler and later v8 manual had engine oil cooler but no transmission cooler

Land rover just couldn't decide where the warm bits were :P

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A/C condensers while being up for the pressures involved are designed to condense refrigerant gas into a high pressure liquid, and consequently have a very low viscosity so I wouldnt advise using one as an oil cooler the matix tubes being far too small, just use the standard LR oil cooler and you should have no problems

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